/*
 *  SableJBDD, a Java Binary Decision Diagram package.
 *  Copyright (C) 2003  Feng Qian
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
//$Id: JBddInternalNode.java,v 1.8 2004/03/15 02:06:55 fqian Exp $

package SableJBDD.bdd;

/**
 * A class for bdd internal nodes. 
 *
 * @author Feng Qian
 */

public final class JBddInternalNode extends JBddNode {
  /**
   * Defines an internal bdd node. To ensure the uniqueness of a bdd node, 
   * the node should only be created from a unique table.
   * 
   * @param v the variable
   * @param l the false branch
   * @param h the true branch
   */
  public JBddInternalNode(JBddVariable v, JBddNode l, JBddNode h) {
    super.variable = v;
    super.low      = l;
    super.high     = h;
  }
  
  /** @return false */
  boolean isConst() {
    return false;
  }

  /** @return the order of this bdd node */
  int getLevel() {
    return super.variable.getLevel();
  }
  
  /** @return the name of the node */
  public String toString() {
    return super.variable.toString();
  }

  /** Allocate an empty BDD node. */
  public JBddInternalNode(JBddNode next) {
    this(null, null, null);
    super.next = next;
  }
}
